// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/*
 * Copyright (c) 2017-2018 Mellanox Technologies. All rights reserved.
 */

#include <rdma/rdma_cm.h>
#include <rdma/ib_verbs.h>
#include <rdma/restrack.h>
#include <linux/mutex.h>
#include <linux/sched/task.h>
#include <linux/pid_namespace.h>

#include "cma_priv.h"
#include "restrack.h"

/**
 * rdma_restrack_init() - initialize and allocate resource tracking
 * @dev:  IB device
 *
 * Return: 0 on success
 */
int rdma_restrack_init(struct ib_device *dev)
{
        struct rdma_restrack_root *rt;
        int i;

        dev->res = kcalloc(RDMA_RESTRACK_MAX, sizeof(*rt), GFP_KERNEL);
        if (!dev->res)
                return -ENOMEM;

        rt = dev->res;

        for (i = 0; i < RDMA_RESTRACK_MAX; i++)
                xa_init_flags(&rt[i].xa, XA_FLAGS_ALLOC);

        return 0;
}

static const char *type2str(enum rdma_restrack_type type)
{
        static const char * const names[RDMA_RESTRACK_MAX] = {
                [RDMA_RESTRACK_PD] = "PD",
                [RDMA_RESTRACK_CQ] = "CQ",
                [RDMA_RESTRACK_QP] = "QP",
                [RDMA_RESTRACK_CM_ID] = "CM_ID",
                [RDMA_RESTRACK_MR] = "MR",
                [RDMA_RESTRACK_CTX] = "CTX",
        };

        return names[type];
};

/**
 * rdma_restrack_clean() - clean resource tracking
 * @dev:  IB device
 */
void rdma_restrack_clean(struct ib_device *dev)
{
        struct rdma_restrack_root *rt = dev->res;
        struct rdma_restrack_entry *e;
        char buf[TASK_COMM_LEN];
        bool found = false;
        const char *owner;
        int i;

        for (i = 0 ; i < RDMA_RESTRACK_MAX; i++) {
                struct xarray *xa = &dev->res[i].xa;

                if (!xa_empty(xa)) {
                        unsigned long index;

                        if (!found) {
                                pr_err("restrack: %s", CUT_HERE);
                                dev_err(&dev->dev, "BUG: RESTRACK detected leak of resources\n");
                        }
                        xa_for_each(xa, index, e) {
                                if (rdma_is_kernel_res(e)) {
                                        owner = e->kern_name;
                                } else {
                                        /*
                                         * There is no need to call get_task_struct here,
                                         * because we can be here only if there are more
                                         * get_task_struct() call than put_task_struct().
                                         */
                                        get_task_comm(buf, e->task);
                                        owner = buf;
                                }

                                pr_err("restrack: %s %s object allocated by %s is not freed\n",
                                       rdma_is_kernel_res(e) ? "Kernel" :
                                                               "User",
                                       type2str(e->type), owner);
                        }
                        found = true;
                }
                xa_destroy(xa);
        }
        if (found)
                pr_err("restrack: %s", CUT_HERE);

        kfree(rt);
}

/**
 * rdma_restrack_count() - the current usage of specific object
 * @dev:  IB device
 * @type: actual type of object to operate
 * @ns:   PID namespace
 */
int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type,
                        struct pid_namespace *ns)
{
        struct rdma_restrack_root *rt = &dev->res[type];
        struct rdma_restrack_entry *e;
        XA_STATE(xas, &rt->xa, 0);
        u32 cnt = 0;

        xa_lock(&rt->xa);
        xas_for_each(&xas, e, U32_MAX) {
                if (ns == &init_pid_ns ||
                    (!rdma_is_kernel_res(e) &&
                     ns == task_active_pid_ns(e->task)))
                        cnt++;
        }
        xa_unlock(&rt->xa);
        return cnt;
}
EXPORT_SYMBOL(rdma_restrack_count);

static void set_kern_name(struct rdma_restrack_entry *res)
{
        struct ib_pd *pd;

        switch (res->type) {
        case RDMA_RESTRACK_QP:
                pd = container_of(res, struct ib_qp, res)->pd;
                if (!pd) {
                        WARN_ONCE(true, "XRC QPs are not supported\n");
                        /* Survive, despite the programmer's error */
                        res->kern_name = " ";
                }
                break;
        case RDMA_RESTRACK_MR:
                pd = container_of(res, struct ib_mr, res)->pd;
                break;
        default:
                /* Other types set kern_name directly */
                pd = NULL;
                break;
        }

        if (pd)
                res->kern_name = pd->res.kern_name;
}

static struct ib_device *res_to_dev(struct rdma_restrack_entry *res)
{
        switch (res->type) {
        case RDMA_RESTRACK_PD:
                return container_of(res, struct ib_pd, res)->device;
        case RDMA_RESTRACK_CQ:
                return container_of(res, struct ib_cq, res)->device;
        case RDMA_RESTRACK_QP:
                return container_of(res, struct ib_qp, res)->device;
        case RDMA_RESTRACK_CM_ID:
                return container_of(res, struct rdma_id_private,
                                    res)->id.device;
        case RDMA_RESTRACK_MR:
                return container_of(res, struct ib_mr, res)->device;
        case RDMA_RESTRACK_CTX:
                return container_of(res, struct ib_ucontext, res)->device;
        default:
                WARN_ONCE(true, "Wrong resource tracking type %u\n", res->type);
                return NULL;
        }
}

void rdma_restrack_set_task(struct rdma_restrack_entry *res,
                            const char *caller)
{
        if (caller) {
                res->kern_name = caller;
                return;
        }

        if (res->task)
                put_task_struct(res->task);
        get_task_struct(current);
        res->task = current;
}
EXPORT_SYMBOL(rdma_restrack_set_task);

static void rdma_restrack_add(struct rdma_restrack_entry *res)
{
        struct ib_device *dev = res_to_dev(res);
        struct rdma_restrack_root *rt;
        int ret;

        if (!dev)
                return;

        rt = &dev->res[res->type];

        kref_init(&res->kref);
        init_completion(&res->comp);
        if (res->type != RDMA_RESTRACK_QP)
                ret = xa_alloc_cyclic(&rt->xa, &res->id, res, xa_limit_32b,
                                &rt->next_id, GFP_KERNEL);
        else {
                /* Special case to ensure that LQPN points to right QP */
                struct ib_qp *qp = container_of(res, struct ib_qp, res);

                ret = xa_insert(&rt->xa, qp->qp_num, res, GFP_KERNEL);
                res->id = ret ? 0 : qp->qp_num;
        }

        if (!ret)
                res->valid = true;
}

/**
 * rdma_restrack_kadd() - add kernel object to the reource tracking database
 * @res:  resource entry
 */
void rdma_restrack_kadd(struct rdma_restrack_entry *res)
{
        res->task = NULL;
        set_kern_name(res);
        res->user = false;
        rdma_restrack_add(res);
}
EXPORT_SYMBOL(rdma_restrack_kadd);

/**
 * rdma_restrack_uadd() - add user object to the reource tracking database
 * @res:  resource entry
 */
void rdma_restrack_uadd(struct rdma_restrack_entry *res)
{
        if (res->type != RDMA_RESTRACK_CM_ID)
                res->task = NULL;

        if (!res->task)
                rdma_restrack_set_task(res, NULL);
        res->kern_name = NULL;

        res->user = true;
        rdma_restrack_add(res);
}
EXPORT_SYMBOL(rdma_restrack_uadd);

int __must_check rdma_restrack_get(struct rdma_restrack_entry *res)
{
        return kref_get_unless_zero(&res->kref);
}
EXPORT_SYMBOL(rdma_restrack_get);

/**
 * rdma_restrack_get_byid() - translate from ID to restrack object
 * @dev: IB device
 * @type: resource track type
 * @id: ID to take a look
 *
 * Return: Pointer to restrack entry or -ENOENT in case of error.
 */
struct rdma_restrack_entry *
rdma_restrack_get_byid(struct ib_device *dev,
                       enum rdma_restrack_type type, u32 id)
{
        struct rdma_restrack_root *rt = &dev->res[type];
        struct rdma_restrack_entry *res;

        xa_lock(&rt->xa);
        res = xa_load(&rt->xa, id);
        if (!res || !rdma_restrack_get(res))
                res = ERR_PTR(-ENOENT);
        xa_unlock(&rt->xa);

        return res;
}
EXPORT_SYMBOL(rdma_restrack_get_byid);

static void restrack_release(struct kref *kref)
{
        struct rdma_restrack_entry *res;

        res = container_of(kref, struct rdma_restrack_entry, kref);
        complete(&res->comp);
}

int rdma_restrack_put(struct rdma_restrack_entry *res)
{
        return kref_put(&res->kref, restrack_release);
}
EXPORT_SYMBOL(rdma_restrack_put);

void rdma_restrack_del(struct rdma_restrack_entry *res)
{
        struct rdma_restrack_entry *old;
        struct rdma_restrack_root *rt;
        struct ib_device *dev;

        if (!res->valid)
                goto out;

        dev = res_to_dev(res);
        if (WARN_ON(!dev))
                return;

        rt = &dev->res[res->type];

        old = xa_erase(&rt->xa, res->id);
        WARN_ON(old != res);
        res->valid = false;

        rdma_restrack_put(res);
        wait_for_completion(&res->comp);

out:
        if (res->task) {
                put_task_struct(res->task);
                res->task = NULL;
        }
}
EXPORT_SYMBOL(rdma_restrack_del);